How to Setup Prometheus Monitoring On Kubernetes Cluster

Prometheus is an open source monitoring framework. Explaining Prometheus is out of scope of this article. In this article, I will guide you to setup Prometheus on a Kubernetes cluster and collect node, pods and services metrics automatically using Kubernetes service discovery configurations. If you want to know more about Prometheus, You can watch all Prometheus related videos from here.

Prometheus Monitoring on Kubernetes

I assume that you have a kubernetes cluster ready with kubectl setup on your workstation. If you don’t have a kubernetes setup, you can setup a cluster on google cloud by following this article.

Latest Prometheus is available as a docker image in its official docker hub account. We will use that image for the setup.

Let’s get started with the setup.

All the configuration files I mentioned in this guide is hosted on Github. You can clone the repo using the following command.

Connect to the Cluster

Connect to your Kubernetes cluster and set up the proxy for accessing the Kubernetes dashboard.

Create a Namespace

First, we will create a Kubernetes namespace for all our monitoring components. Execute the following command to create a new namespace called monitoring.

Create a Config Map

We should create a config map with all the prometheus scrape config which will be mounted to the Prometheus container in /etc/prometheus as prometheus.yaml file. This config map contains all the configuration to dynamically discover pods and services running in the kubernetes cluster.

1. Create a file called config-map.yaml and copy the contents of this file –> Prometheus Config File

2. Execute the following command to create the config map in kubernetes.

Create a Prometheus Deployment

1. Create a file named prometheus-deployment.yaml and copy the following contents onto the file. In this configuration, we are mounting the Prometheus config map as a file inside /etc/prometheus. It uses the official Prometheus image from docker hub.

4. Create a deployment on monitoring namespace using the above file.

5. You can check the created deployment using the following command.

You can also get details from the kubernetes dashboard like shown below.

prometheus on kubernetes

Connecting To Prometheus

You can connect to the deployed Prometheus in two ways.

  1. Using Kubectl port forwarding
  2. Exposing the Prometheus deployment as a service with NodePort or a Load Balancer.

We will look at both the options.

Using Kubectl port forwarding

Using kubectl port forwarding, you can access the pod from your workstation using a selected port on your localhost.

1. First, get the Prometheus pod name.

The output will look like the following.

2. Execute the following command with your pod name to access Prometheus from localhost port 8080.

Note: Replace prometheus-monitoring-3331088907-hm5n1 with your pod name.

3. Now, if you access http://localhost:8080 on your browser, you will get the Prometheus home page.

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Exposing Prometheus as a Service

To access the Prometheus dashboard over a IP or a DNS name, you need to expose it as kubernetes service.

1. Create a file named prometheus-service.yaml and copy the following contents. We will expose Prometheus on all kubernetes node IP’s on port 30000.

Note: If you are on AWS or Google Cloud, You can use Loadbalancer type, which will create a load balancer and points it to the service.

2. Create the service using the following command.

3. Once created, you can access the Prometheus dashboard using any Kubernetes node IP on port 30000. If you are on the cloud, make sure you have the right firewall rules for accessing the apps.

4. Now if you go to status –> Targets, you will see all the Kubernetes endpoints connected to Prometheus automatically using service discovery as shown below. So you will get all kubernetes container and node metrics in Prometheus.

prometheus kubernetes target configuration

5. You can head over the homepage and select the metrics you need from the drop-down and get the graph for the time range you mention. An example graph for container memory utilization is shown below.

prometheus kubernetes metrics

In the next article, I will be covering pod monitoring using custom application metrics and set up alert rules and alert manager for Prometheus. Subscribe to the email list to get the new article updates.


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2 comments

  1. Alok T Reply

    Thanks a Ton !! I am new to Kubernetes and while Exposing Prometheus As A Service i am not getting external IP for it. My Graphana dashboard cant consume localhost. Can you please guide me how to Exposing Prometheus As A Service with external IP.

    Thanks
    Alok

  2. Greg K. Reply

    Thanks for the tutorial.
    Looks like the arguments need to be changed from
    “-config.file=/etc/prometheus/prometheus.yml”
    and
    “-storage.local.path=/prometheus/”

    to

    “–config.file=/etc/prometheus/prometheus.yml”
    “–storage.tsdb.path=/prometheus/”

    Thank again!

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